The standard Fast Spin Echo sequence used in MR imaging relies on the CPMG condition. A consequence of this condition is that only one component of the transverse magnetization can be measured. To counter this, some phase modulation schemes (XY, MLEV.) for the pulse train have been proposed, but they are useful only over a very restricted range, close to pi, of the refocusing pulse rotation ang...

A direct-modulation OEO (DM-OEO) generating stable 10 GHz and 20 signals is presented. single loop a dual approach are implemented compared. We show an output signal of 15 dBm RF power, phase noise as low −135 dBc/Hz at kHz offset from the carrier. The second harmonic exhibits level −127 kHz. high spur reduction also obtained in architecture.